Seduced by a Spy (Merlin's Maidens)

They were once orphans from London's roughest slums. Now they are students of Mrs. Merlin's Academy for Select Young Ladies, learning the techniques of spying and seduction. Bold, beautiful, and oh-so-dangerous, they are England's ultimate secret weapons...
Hot-tempered and a warrior to the bone, Shannon is the most daring of "Merlin Maidens." Her assignment: stop the fiendishly cruel assassin who is targeting a top British ballistics expert's family. Marshalling her intelligence, fighting skills, and weapons is easy. Being forced to work with the rakishly handsome Russian spy she loathes is something else.
Witty, resourceful, and notorious for his rakish charm with women, Alexandr Orlov tempts Shannon's fierce reserve and lithe body to win her trust. But in the remote Scottish castle where they are sent to protect the innocent, their games of parry and thrust could end in death. A ruthless enemy is watching...and planning to turn their passion into the most dangerous weapon of all.